The Applicant has developed a wide range of printers that employ pagewidth printheads instead of traditional reciprocating printhead designs. Pagewidth designs increase print speeds as the printhead does not traverse back and forth across the page to deposit a line of an image. The pagewidth printhead simply deposits the ink on the media as it moves past at high speeds. Such printheads have made it possible to perform full colour 1600 dpi printing at speeds in the vicinity of 60 pages per minute, speeds previously unattainable with conventional inkjet printers.
The high print speeds require a large ink supply flow rate. Not only are the flow rates higher but distributing the ink along the entire length of a pagewidth printhead is more complex than feeding ink to a relatively small reciprocating printhead.
Some of the Applicant's printers provide the printhead as a user removable cartridge. This recognizes that individual ink ejection nozzles may fail over time and eventually there are enough dead nozzles to cause artifacts in the printed image. Allowing the user to replace the printhead maintains the print quality without requiring the entire printer to be replaced. It also permits the user to substitute a different printhead for different print jobs. A draft quality printhead can be installed for some low resolution documents printed at high speed, and subsequently removed and replaced with the original high resolution printhead.
A number of the Applicant's printhead cartridges do not have an inbuilt ink supply for the printhead. These printhead cartridges need to be fluidically coupled to the ink supply upon installation. The supply flowrate to the pagewidth printhead is too high for needle valves because of the narrow internal diameter. This requires the coupling conduits to be relatively large and therefore the engagement force required during installation is relatively high. The fluid seal is provided by a resilient element that is deformed during engagement. With larger conduits, the resilient element is larger and so to is the force required to deform it. Furthermore, full color printheads will have 3, 4 or even 5 separate couplings (CMY, CMYK, CMYKK or CMYK,IR) which only multiplies the additional coupling force necessary. Modern market expectations are that the installation and removal of cartridges and other consumables are simple and physically easy. It is also structurally undesirable to subject the cartridge to large forces. Flexing or bowing of the cartridge body can stress the electronics or nozzle structures.